At present, automotive companies are increasing production of gasoline-electric hybrid vehicles, and research on pure electric and fuel cell powered vehicles. These electrically assisted and powered vehicles have the potential for reduced emissions, improved fuel economy, and enhanced performance. These advantages are possible because the electric component of the electric or hybrid engine allows near silent operation, precision control, added engine torque and power with a surge potential, and energy recovery from regenerative braking. With regard to regenerative braking, batteries and ultra-capacitors can be recharged, and fuel cell powered vehicles usually have battery or ultra-capacitor components.
Electrically assisted and powered vehicles generally disconnect the battery pack from the vehicle electrical wiring system when the vehicle is powered off. This serves a number of purposes, for example, isolation of the battery pack from the vehicle electrical loads to thereby reduce parasitic leakage current which drains the battery. Isolation also prolongs the storage of usable power and enhances battery cycle life. Since the battery system is high voltage, isolation furthermore prevents electrical hazards by powering down the myriad of wires and contacts that could be exposed.
The high voltage electrical system of these electrically assisted and powered vehicles can be divided into two main parts: the high voltage energy source including the batteries, ultra-capacitors, fuel cells, and battery pack controller; and the high voltage energy load including the electric motors, wiring, cables, electrical bus, electric coolers and heaters, connectors to the vehicle electrical system, voltage regulators, and many other electrical devices. Between the high voltage energy source and the high voltage energy load is a connection system that can be deactivated to isolate the high voltage energy source from the high voltage energy load.
The high voltage energy load could possibly become shorted to the vehicle body or another wire. In order to protect the vehicle and its users, it is desirable to have a high voltage system connection monitoring system that reliably protects against inadvertently putting full current through a short in the high voltage electrical bus. Other desirable features and characteristics of embodiments of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.